Never been to the Museum of the City of New York? Here’s an incentive: twenties cocktails, views of the Central Park Conservatory Gardens, and fascinating exhibits like “Mannahatta/Manhattan: A Natural History of New York City.” Every Wednesday through August 26, the museum is hosting “Speakeasy” events in its beautiful front courtyard. From 6 to 9 p.m., a $12 admission includes a drink and access to first-floor galleries (1220 Fifth Ave., at 103rd St.;212-534-1672).